Anterior Chamber Air Bubble to Achieve Graft Attachment After DMEK: Is Bigger Always Better?

Purpose: To analyze the influence of the size of the air bubble subsequent to Descemet membrane endothelial keratoplasty (DMEK) surgery on the rate of graft detachment and need for rebubbling, the incidence of pupillary block, and the observed endothelial cell loss.

Methods: This is a single-center, retrospective, consecutive case series of 74 cases undergoing DMEK and fulfilling the inclusion criteria concerning the size of the air bubble at the end of surgery. Based on the medical records, patients were divided into 2 groups (n = 37, respectively). The first group had an air bubble with a volume of approximately 50% and the second group of approximately 80% of the anterior chamber (AC) volume, respectively. Patients who did not comply with instructions to remain in the supine position until complete resorption of AC air or cases in which difficulties in graft preparation (eg, radial breaks) occurred were excluded from data analysis. The central corneal thickness and endothelial cell density were measured 6 months after surgery.

Results: Ten of 37 patients (27.0%) in the 50% air bubble group and 3 of 37 patients (8.1%) in the 80% air bubble group needed 1 rebubbling procedure (P = 0.032). There was no difference between the groups after 6 months regarding endothelial cell density and central corneal thickness. No pupillary block was observed.

Conclusions: Larger air bubbles of 80% anterior chamber volume decrease the risk of graft detachment after DMEK with no detrimental effect on the outcome and risk for pupillary block.